The ever-increasing demand for smaller sized mobile devices, such as cell phones, digital cameras, etc., correspondingly has triggered a growing need for a smaller sized photography module, comprising elements such as an optical imaging lens, a module housing unit, and an image sensor, etc., contained therein. Size reductions may be obtained from various aspects of the mobile devices, which includes not only the charge coupled device (CCD) and the complementary metal-oxide semiconductor (CMOS), but also the optical imaging lens mounted therein. When reducing the size of the optical imaging lens, however, achieving good optical characteristics becomes a challenging problem.
The following publications, U.S. Pat. No. 7,277,238, U.S. Patent Publication No. 2012/0281299 and PCT Patent Publication No. WO 2009/122897 disclose an optical imaging lens constructed with four lens elements, wherein the length of the optical imaging lens is too long for smaller sized mobile devices. Therefore, there is a need to develop optical imaging lens capable of placing four lens elements therein, with a shorter length, while also having good optical characteristics.